fn main() {
    let haystack = vec![
        "Zig", "Zag", "Wally", "Ronald", "Bush", "Krusty", "Charlie", "Bush", "Boz", "Zag",
    ];

    println!(
        "First occurence of 'Bush' at {:?}",
        haystack.iter().position(|s| *s == "Bush")
    );
    println!(
        "Last occurence of 'Bush' at {:?}",
        haystack.iter().rposition(|s| *s == "Bush")
    );
    println!(
        "First occurence of 'Rob' at {:?}",
        haystack.iter().position(|s| *s == "Rob")
    );
}
